1. Introduction
This invention is in the field of devices used to apply microcurrent treatment such as used for application of microcurrent treatment to portions of the human body. Microcurrent therapy is distinct from other methods of applying electromagnetic fields to living tissue. The name microcurrent therapy stems from the use of microamperes as opposed to milliamperes used in TENS devices such as the D""Alerta device disclosed below.
This invention is directed to providing a device that is useful in microcurrent therapy. The device is then used then used in a biological application to provide relief or treatment to tissue and joints. In order to provide context to the use of the invention, the description will include references to the use of the device in connection with the extended application of a microcurrent running through the tissue of the user of the device. Analogous to the variations in the response of various individuals with various maladies to drug therapy, there are many variations in individual response to microcurrent therapy. Although the present invention provides a device that can provide a sustained current flow within a desired microcurrent range, this does not remove all of the other biological variations between users.
One of the requirements of the patent process is to provide the best mode of using the invention. The inventor of the present invention has not invented microcurrent therapy nor has the inventor personally directed controlled studies that determined optimal placement and current application regimes for microcurrent devices. Thus the best mode provided by the inventor for the present invention relates to the microcurrent therapy device and the method of indicating a current flow through the tissue. It is expected that as this field is further developed by those skilled in developing such microcurrent therapies, that one skilled in the art of making microcurrent therapy devices will be able to adapt the disclosed invention to provide the specific requested microcurrent therapy.
2. Description of the Prior Art
A device for use in the application of therapeutic microcurrent to tissue is disclosed in U.S. Pat. No. 5,354,321 to Mario Berger. The ""321 patent discloses a Patch Arrangement for Galvanic Treatment. The Abstract of the Berger patent asserts that the ""321 invention is based on the object to employ electrotherapy through stable galvanization without an external voltage source to provide an efficient and practical device. Rather than repeat all that is taught in the Berger patent, the U.S. Pat. No. 5,354,321 is hereby incorporated by reference.
The Berger patent builds on earlier inventions to apply metal plates to the surface of the skin on both sides of the effected area. By selecting a particular arrangement of dissimilar metals and insulators, one can produce a flow of current through skin and the tissue below the skin as this portion of the body provides an electric bridge between plates of dissimilar metals. The circuit path between the two dissimilar metal plates allows a small current on the order of microcurrents to flow through the tissue until this Galvanic current is no longer present. The Berger patent asserts that the use of a series of pairs of dissimilar metals can be used to improve the prior art devices by increasing the Galvanic current effect.
As noted in column three of the Berger ""321 patent, there may be times where an electrically conductive material will be applied between the skin and the metal electrodes in order to reduce the electrical resistance between the metal electrodes and the skin. The material will need to be electrically conductive but can be any one of a number of materials that can be left in contact with the skin such as a material containing or soaked with an electrolyte. Perspiration carries various electrolytes. Thus a piece of fabric soaked in perspiration would serve as an electrically conductive material.
Unfortunately, skin, tissue, and perspiration are not manufactured items with constant electrical properties. These materials vary both between individuals and even at different times and places for the same individual. An individual that has dry skin in the winter is likely to have different electrical properties in the skin than the same person would have in the summer while playing tennis and perspiring heavily. The use of a conductive gel helps with dry skin but adds its own source of variability in its level to conductivity. Various gels are used for medical reasons to promote xe2x80x9cgood contactxe2x80x9d between the skin and various monitoring devices. While it may not matter the specific electrical conductivity of a dab of gel for use in getting xe2x80x9cgood contactxe2x80x9d for a monitoring device, the same is not true for a microampere current flow that is intended to be kept within a narrow range of current flow rates.
Since there are several factors which lead to variability in the electrical properties of skin, tissue, and the gels used to promote good contact, it then follows that the electrical properties of the skin and tissue vary from one person to another and even for one person from one week to another. The variation in electrical properties cause variations in the flow rate of current and the effective life of the current source for therapeutic device. The use of various types of conductive gels, the thickness and uniformity of application of the gel, the amount of perspiration on the skinxe2x80x94all add to the variability. Yet, another source of variability is the cleanliness of the surface of the metal pads in the Gerber device.
The net effect of all these variations causes considerable variation in current flow. In some cases the current flow from a Galvanic device can be below the level of current flow desired for therapeutic action. In other cases the same device can provide a current flow that not only exceeds the desired levels but actually causes a painful burning sensation.
U.S. Pat. No. 5,423,874 to D""Alerta discloses a Patch for Applying Pain Reducing Electrical Energy to the Body. The D""Alerta patent describes another type of device, a TENS device that is used to block the sensation of pain without any rejuvenative effect to the tissue. This D""Alerta ""874 patent is incorporated by reference into this description but will be briefly described.
One of the many differences between the ""874 device and the Berger Galvanic device in that the ""874 includes xe2x80x9con-board circuitryxe2x80x9d to provide additional control beyond the constant application of a decaying Galvanic voltage potential. The ""874 patent includes an integrated circuit and other circuitry for creation of a series of 50 volt square waves. (In other words the voltage quickly rises to 50 volts DC, is maintained at that voltage for a fixed period of time, falls quickly to 0 volts and then stays at 0 volts for a fixed period of time before repeating the pattern.)
Although the D""Alerta device is for delivering current at milliampere rather than microampere levels (approximately 1000xc3x97the levels of current delivered in a microcurrent device), the D""Alerta device is included here to highlight a use of an LED indicator light. The D""Alerta device provides a 50 volt pulse to the skin and is easily perceived by the user. The LED light as placed in FIG. 7 as Element CR1 indicates whether the timing clock signal on pin 3 of IC1 and the battery V1 are operating. Thus, the indicator LED of the D""Alerta device is not in line with the current path through the user between the Anode Pad and the Cathode Pad and thus does not indicate the successful application of current through the user""s skin.
3. Problems with Prior Art Solutions
The name microcurrent therapy stems from the use of microamperes as opposed to milliamperes used in TENS devices. One of the results of using such low current levels is that the user of a microcurrent therapy device (xe2x80x9cMCTDxe2x80x9d) is often unable to tell when the device is applying a therapeutic dose of microcurrent or when the device is simply not working at all. While it is desirable that the operation of the MCTD does not cause discomfort to the person receiving therapy, there are two major problems with being imperceptible the user.
The first problem a false positive conclusion that a MCTD unit that has been damaged, improperly used, or used beyond its useful life will be used for an extended period of time without any application of microcurrent to the target site. False positive conclusions are harmful in that they interfere with effective treatment and lead users to believe that microcurrent therapy will not be useful to the user.
The second problem is a false negative conclusion that some users will mistakenly believe that a functioning MCTD is not operating and will then remove and discard functional MCTD units. If a new user receives a device that does not give any readily perceptible indication that the device is working, the new user may return the device to the place of purchase for a refund. The returned device having been opened and placed in contact with the user""s skin would not be marketable to another user.
False negative conclusions are harmful in that the cost of treatment goes up as functional units are discarded and the user may view the provider of the microcurrent therapy devices in a negative light for providing non-functioning units.
One possible solution is the addition of a switch to the MCTD. Under this solution, the MCTD is activated by pressing downward on the center of the MCTD. The unit is equipped with a small pressure activated switch that provides both an audible sound and a small mechanical vibration to provide a tactile feel to the person activating the unit. Although the addition of a pressure activated switch would be an improvement over prior art solutions, the use of a switch is imperfect as someone who has operated the switch may not be sure if it worked, or may activate the switch several times to see if the MCTD current can be perceived. One problem with operating a switch several times is that the user may lose confidence that the user remembers how many times the switch has been activated. The user may wonder xe2x80x9cWas it an odd number of times (the unit is on) or an even number of times (the unit is off)xe2x80x9d? If the user is unable to perceive the flow of the microcurrent, the user is now tempted to keep switching the unit on and off throughout the period of intended application to hedge the user""s bet. Unfortunately hedging the bet on switch position leads to undesired interruptions in the application of microcurrent therapy.
Another potential solution is the use of an indicator such as an LED corresponding circuit such as used in the D""Alerta device. However, the LED indicator wired as shown in the D""Alerta device would be only a partial solution since the LED would merely indicate that the battery is working and would not provide an indication on the existence of substantial current flow the tissue.
Thus, the prior designs do not provide a suitable solution to the problem of determining whether an imperceptible amount of current is passing through the user""s skin and the underlying tissue.
A solution to the problem must not cause other undesired consequences in the context of applying therapeutic microcurrents for extended periods to ambulatory users. The therapeutic device needs to be suitable to affix to a variety of locations on a human body. The therapeutic device needs to move with the user for an extended period of time (on the order of days or weeks). The microcurrent therapy device needs to be designed so that it can be used during physical activity including but not limited to golf, swimming, tennis, basketball, biking, and long distance running. In order to reduce the problems associated with limiting or inhibiting movement, it is important for the device to be flexible and have a low profile so that the device is more like another set of skin than an electrical box taped to the user. Having a low profile increases the chance that the user can wear his or her regular sports clothing, including the various types of tight fitting clothing used for various sport activities.
Because a microcurrent device is typically used for an extended period of time, it is important to provide a device that will provide a relatively uniform current flow over the intended period of use.
It is an advantage to create a device that consumes power sparingly so that the useful life of the microcurrent therapy device is extended for a given battery. While it could work to add additional batteries or a battery with a longer life to the microcurrent therapy device, these additional or more powerful batteries add some combination of size, weight, or cost to the microcurrent therapy device.
In order to keep costs down, it is preferred that the microcurrent therapy device be able to use readily available batteries so that the non-recoverable engineering costs of establishing a process and an assembly line for a battery is amortized over so many batteries that it becomes essentially negligible.
Briefly, the present invention is directed to an electronic stack that can be placed in a microcurrent therapy device in electrical connection with the user""s skin and in electrical connection with the other skin contact plate. The present invention includes a profile minimizing system of using an off the shelf xe2x80x9ccoinxe2x80x9d battery within the electronic stack. The present invention includes an indicator (in this case an LED light) to indicate that the current path through the skin is operating. The circuitry chosen for this device provides a relatively uniform delivery of therapeutic microcurrent over an extended period of time by making efficient use of power drawn from the battery.